Gas chromatography (GC) with flame-ionization detection has been used to measure the catecholamine metabolites homovanillic acid (HVA), vanillylmandelic acid (VMA), and methoxyhydroxyphenyl glycol (MHPG) in human urine. Gas chromatography-mass spectrophotometry has been used to verify the purity of GC peaks obtained. Present methods are simpler than existing methods which employ electron-capture detection or mass fragmentography.